screen pixelating constantly for months while watching Comcast programs

For many months now I have encountered this issue no matter which HD channels I am watching. Why does this continue to happen? This occurs at least 10 times an hour and lasts about 2-3 seconds. When this does occur I will miss the audio/video for that duration as well. To say this is disruptive to my viewing experience is an understatement. I have previous refreshed my cable box and followed the system refresh instructions. Those tasks did nothing to correct the problem.
Today I am watching programming on the DVR and live TV, and the pixelating continues non stop. I cannot watch anything on Comcast without this happening.

 Can someone please have this checked out?